Lay-up independent fracture criterion for notched laminated composites

The purpose of this study was to investigate the applicability of an existing lay-up independent fracture criterion for notched composite laminates. A detailed finite element analysis of notched graphite/epoxy laminates was performed to understand the nature of stresses and crack tip parameters in finite-width composite panels. A new laminate parameter β, which plays a crucial role in the fracture of laminated composites, has been identified. The effects of blunt crack tip and local damage on fracture behavior of notched composite laminates are investigated using the finite element analysis. The results of experiments performed elsewhere are analyzed in the light of new understanding of crack tip stress field, and the applicability of the lay-up independent fracture criterion for notched composite laminates is discussed. It is found that a lay-up independent fracture model that considers local damage effects provides good correlation with the experimental data.